A principle consideration for the design and construction of a new commercial and industrial building is to provide buffering for storm water runoff anticipated in the construction of large scale flat or low pitched roofs

The impervious nature of large scale developments means that there is little water retention by the surfaces on which the water falls, creating the need for efficient gutter and disposal systems

The provision of a simple sedum mat green roof over an industrial building will provide an immediate 60% increase in its ability to absorb storm water, creating water buffering and a significant reduction to the threat of flooding arising from short ,intensive, summer storms

The city of Rotterdam study following  flooding in 2002, revealed the conversion of 25% of its flat roof area into Sedum roofing would have provided sufficient capacity to absorb the excess rainwater and prevent a multi million pound disaster

This benefit  is recognised by planners and strategic development authorities and Green Roofs are now a design requirement in a number of European Cities